// 基于下列代码完成任务
const fp = require('lodash/fp');
const cars = [
  {
    name: 'Ferrari FF',
    horsepower: 660,
    dollar_value: 700000,
    in_stock: true
  },
  {
    name: 'Spyker C12 Zagato',
    horsepower: 650,
    dollar_value: 648000,
    in_stock: false
  },
  {
    name: 'Jaguar XKR-S',
    horsepower: 550,
    dollar_value: 132000,
    in_stock: false
  },
  {
    name: 'Audi R8',
    horsepower: 525,
    dollar_value: 114200,
    in_stock: false
  },
  {
    name: 'Aston Martin One-77',
    horsepower: 750,
    dollar_value: 1850000,
    in_stock: true
  },
  {
    name: 'Pagani Huayra',
    horsepower: 700,
    dollar_value: 1300000,
    in_stock: false
  },
]

// 2.1 优化isLastInStock函数
let isLastInStock = fp.flowRight(fp.prop('in_stock'), fp.last);
console.log(isLastInStock(cars));

// 2.2 使用fp.flowRight、fp.prop、fp.first获取第一辆车的name
let f = fp.flowRight(fp.prop('name'), fp.first);
console.log(f(cars));

// 2.3 使用帮助函数_average重构averageDollarValue, 使用函数组合方式实现
let _average = function (xs) {
  return fp.reduce(fp.add, 0, xs) / xs.length;
}
let averageDollarValue = fp.flowRight(_average, fp.map(car => car.dollar_value));
console.log(averageDollarValue(cars));

// 2.4 使用flowRight写一个sanitizeNames函数，返回一个下划线连接的小字符串，把数组中的name转换成一下这种形式
// sanitizeNames(['Hello World']) => ['hello_world']
let _underscore = fp.replace(/\W+/g, '_');
let sanitizeNames = fp.flowRight(fp.map(fp.toLower), fp.map(_underscore), fp.map(car => car.name));
console.log(sanitizeNames(cars));
